Modelling the Effect of Variable Viscosity on Unsteady Couette Flow of Nanofluids with Convective Cooling


1 Nelson Mandela African Institution of Science and Technology (NM-AIST), Arusha, Tanzania.

2 Faculty of Military Science, Stellenbosch University, Private Bag X2, Saldanha 7395, South Africa.


This paper investigates numerically the effects of variable viscosity on unsteady generalized Couette flow of a water base nanofluid with convective cooling at the moving surface. The Buongiorno model utilized for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The nonlinear governing equations of continuity, momentum, energy and nanoparticles concentration are tackled numerically using a semi discretization finite difference method together with Runge-Kutta Fehlberg integration scheme. Numerical results for velocity, temperature, and nanoparticles concentration profiles together with skin friction and Nusselt number are obtained graphically and discussed quantitatively.